mstern, Not only do I think I know who you are talking about but I think I owned that boat after the idiots almost sank it. Just a guess but did you run into them in the Hew Haven CT area? If so...they did not die, Darwin was wrong.
As far as reporting something to the locals or Coast Guard, YES you need to. If something seems wrong chances are it is wrong and you have a moral and legal responsibility to report it.